1. Field of the Invention
The present invention relates to an improvement of the milling cutter which is used to cut the contaminated surface of concrete at the time of repairing and dismantling nuclear facilities.
2. Prior Art
As the number of nuclear facilities increases, it is necessary to previously study those techniques which will be needed at the sites of large-scaled repairing and dismantling works in the future.
We inventors of the present invention have disclosed from this viewpoint a technique of cutting the contaminated surface of concrete in Japanese Patent Application Nos. 58-153740 and 58-157406. We have also disclosed an improvement of the milling cutter in Japanese Utility Model Application No. 59-10292.
As the milling cutters for use with the contaminated concrete surface cutting apparatus, there have been well known those which comprise embedding ultra-hard chips or diamond chips on the outer circumferential surface of the rotating drum, but the cutting depth to which the contaminated surface of concrete is cut by these cutting apparatuses ranges from 1mm to 3mm and their maximum cutting capacities per hour reach only 5m.sup.2 or less. These values were not satisfactory to us and it was also impossible to cut aggregates in concrete.
Further when the chips were used up, it took a long time to exchange them with new ones and embed them on the outer circumferential surface of the drum.